And since they are satellite hosted repos, they are yours to control and to populate. All we can do is tell you that you need to entirely replace both base and updates every time there is a new point release (which may never happen for CentOS 6 as 6.10 may be the last). If you had a 6.9 repo then you cannot just copy the 6.10 repo over the top of it. You need to follow the instructions in the wiki entry to combine the old updates into the old base and then rsync on top of both. Or, easier, just sync the new 6.10 repo to a 6.10 directory and use a symlink to flip between one and the other.

All we can say for sure is that your copy of the repo is incorrect.

CentOS 5 died in March 2017 - migrate NOW!
Full time Geek, part time moderator. Use the FAQ Luke